Changes of High-Temperature Damage to Double Cropping Rice of Six Counties (Cities) in Southwest Guangxi and Countermeasure

【Objective】This paper studied the temporal and spatial distribution relationship of comprehensive high temperature damage index and yield reduction rate in southwest Guangxi, and explored the spatial distribution law of high temperature damage to double cropping rice in order to provide reasonable suggestions for rice planting in this area to avoid losses and ensure food security.【Method】The comprehensive high temperature damage index, based on the Logistic model, were used to evaluate the high temperature damage situation and temporal and spatial variation of double cropping rice of 6 counties(cities) in southwest Guangxi.【Result】The results showed that the average reduction rate of early rice of the 6 counties(cities) in southwest Guangxi increased notably from 7% in 1980s to 22.4% in the early 21st century and the average reduction rate of late rice increased significantly from 17.6% in 1980s to 22.1% in the early 21st century. The high temperature was one of the main causes of the increase of reduction rate, and the loss of rice was serious because of high temperature. The intensity of double-cropping rice affected by high temperature damage was various in the different regions of southwest Guangxi, and the intensity of early rice affected by high temperature damage showed a rising trend in fluctuation, with the lowest intensity appearing in the 1990s while the highest intensity appearing in the early 21st century. The intensity of late rice affected by high temperature was weak and the intensity did not fluctuated sharply expect that the relatively high intensity appeared in 1990s.【Conclusion】 Since the 1980s, partial key growth stages of early rice did not fall into the period with high temperature, and this could be avoided by applying fertilizer or plant growth regulator at the early stage. For late rice, given the test results of Guangdong Province, the sowing time could be postponed to July to avoid the concentrated period of high temperature and ensure the stability of food security.